package com.bestdreamer.example.commonUnsafe;

import com.bestdreamer.annoations.NotThreadSafe;
import lombok.extern.slf4j.Slf4j;

import java.text.ParseException;
import java.text.SimpleDateFormat;
import java.util.concurrent.CountDownLatch;
import java.util.concurrent.ExecutorService;
import java.util.concurrent.Executors;
import java.util.concurrent.Semaphore;

/**
 * 运行抛出异常
 * 原因：SimpleDateFormat 不是线程安全对象，所以多线程下运行容易出现问题
 */
@Slf4j
@NotThreadSafe
public class DateFormatExample1 {

    private static final SimpleDateFormat simpleDateFormat = new SimpleDateFormat("yyyyMMdd");

    // 请求总数
    public static int clientTotal = 5000;
    // 同时并发执行的线程数
    public static int threadTotal = 200;

    public static void main(String[] args) throws InterruptedException {
        ExecutorService executorService = Executors.newCachedThreadPool();
        final Semaphore semaphore = new Semaphore(threadTotal);
        final CountDownLatch countDownLatch = new CountDownLatch(clientTotal);
        for( int i = 0; i < clientTotal ; i++){
            executorService.execute(() -> {
                try{
                    semaphore.acquire();
                    update();
                    semaphore.release();
                }catch (Exception e) {
                    log.error("exception", e);
                }
                countDownLatch.countDown();
            });
        }
        countDownLatch.await();
        executorService.shutdown();
    }

    private static void update(){
        try {
            simpleDateFormat.parse("20180208");
        } catch (ParseException e) {
            log.error("parse except",e);
        }
    }

}
